The use of carbon-carbon composite brake disc assemblies in aircraft brakes, which have been referred to as carbon brakes, is well known in the aerospace industry. Carbon-carbon composite brake disc assemblies are manufactured by aircraft wheel and brake manufacturers using a variety of manufacturing methods, which generally require lengthy fabrication and densification methods. In recent years, aircraft manufacturers have increasingly specified the use of such carbon-carbon composite brake disc assemblies for brakes designed for use with new aircraft models.
Typically, a carbon-carbon composite brake disc of a brake disc assembly has either a plurality of circumferentially spaced-apart slots about the circumference of a central opening, which receive splines of an adjacent torque tube, or a plurality of circumferentially spaced-apart slots about the circumference of the outer diameter of the brake disc, which receive drive keys of an adjacent aircraft wheel. The splines of the torque tube and the drive keys of the wheel are usually made of metal. As is well known in the aircraft wheel and brake industry, the spaced-apart slots of the brake disc may each include a metal insert to provide a metal-to-metal interface between the brake disc and either the spline of the torque tube or the drive key of the wheel. The metal-to-metal interface reduces the wear of the spaced-apart slots in the carbon-carbon composite brake disc, and also reduces chipping of the slots, which can occur as a result of loads exerted on the surfaces of the slots.
However, the use of metal inserts may require that holes be drilled into the carbon-carbon composite brake disc so the metal inserts can be riveted to the disc, which increases machining and assembly time, and results in an increase the cost of manufacturing the brake disc. Additionally, the rivets are expensive to purchase and to install as well as add additional weight to the brake disc. Each rivet requires a hole to be drilled to accommodate it in the carbon-carbon composite piece and in the metal insert itself, which is also labor intensive. In addition, the rivets often break allowing the metal insert to be disconnected from the carbon-carbon composite piece.